If the Bottle leaves the battlefield or your control, the cards remain waiting until played or until the beginning of your next upkeep. The card is in the “Exile” zone.

10/4/2004

The card is not part of your hand in any way. You can’t be forced to discard it due to a discard from hand effect, and you can’t discard it to pay a cost.

10/4/2004

To “play a card” is to either cast a spell or to put a land onto the battlefield using the main phase special action.

8/1/2008

If you do not play the card before your next upkeep, it remains exiled; you just lose the ability to play it.

10/1/2008

The exiled card is played using the normal timing rules for its card type, as well as any other applicable restrictions such as “Cast [this card] only during combat.” For example, you can’t play the card during an opponent’s turn unless it’s an instant or has flash. Similarly, if the exiled card is a land, you can’t play it if you’ve already played a land that turn. If it’s a nonland card, you’ll have to pay its mana cost. The only thing that’s different is you’re playing it from the Exile zone.